1. Field of the Invention
The invention relates to a rotary snow plough having feed ploughs attached to one or to both sides of its housing in order to increase the intake cross section.
2. Brief Description of the Prior Art
Depending on the desired clearing width, it is known to extend rotary snow ploughs on one or both sides of the rotary element(s) of the plough. These extensions, which are in the form of so-called feed ploughs, form, as it were, a funnel running towards the rotary cross section.
It has been shown that where relatively large amounts of snow are involved, and particularly in the case of wet snow, blockage occurs in the region of the intake cross section in such rotary snow ploughs, even at the customary clearing speeds. As a result, it becomes impossible for any more snow to enter the rotary stage and, instead, the piled-up mass of snow is pushed along in front of the vehicle. The effects of this phenomenon are especially adverse in a typical area of application for such rotary snow ploughs, namely airfields, where high clearing and conveying speeds (up to about 30 km/h) are essential.
This disadvantage can be avoided by using rotary snow ploughs (German Patent Specification No. 27 21 411) which have endless clearing screws rotating about vertical axes on both sides of the throwing wheel or ejecting fan forming the rotary stage of the plough and in front of the wheel housing in the direction of clearing. These endless clearing screws keep the entrapped snow moving, and convey it from the ground upwards to a point in front of the throwing wheel or fan, so that any packing or accumulation of the snow is avoided.
An arrangement, even though it is less effective, for removing snow in the region of the intake cross section of a rotary snow plough consists of an endless conveyor screw which is arranged along one lateral wall of the plough housing with its longitudinal axis guided obliquely forwards and downwards (DE-OS No. 2 039 187). This prevents a mass of snow from accumulating against the projecting lateral wall of the housing.
Finally, in a rotary snow plough for railway vehicles having cutting rollers rotating about vertical axes arranged in front of the throwing wheel (US-PS No. 931,559), it is known to transport the snow that has been taken from the region of the track by the cutting rollers to the throwing wheel or ejecting fan, by means of a conveyor belt that is approximately parallel with the ground. It is intended thereby that even the snow present in the region of the track shall be taken up, thus enabling it to be drawn into the ejecting fan.